This invention relates to self-sealing septa.
Self-sealing septa are used in medico-surgical and other apparatus to form a seal with the outside of a needle or similar device inserted in the septa, which closes when the needle is withdrawn. For example, a septum in the hub of a catheter might seal with a needle used to introduce the catheter into the body of the patient. When the needle is withdrawn from the catheter, the septum closes to prevent escape of blood through the catheter hub.
One problem with self-sealing septa is that the rubber-like material of the septum changes characteristics as it ages and may make a less effective seal. This is especially the case where the septum is stored for prolonged periods with a needle, or the like, inserted in the septum. In such circumstances, the material of the septum tends to set into its deformed state and produces a lower sealing force when the needle is withdrawn. Attempts have been made to overcome this problem, such as described in, for example, EP 415653. Although this arrangement can help alleviate the problem, it is not universally satisfactory.